1. Field of the Invention
This invention relates to a novel filler for separating an optical isomer, and more specifically it relates to a filler which is capable of separating optical isomers from one another by a column process.
2. Description of the Prior Art
For separating an optical isomer such as amino acid or the like, various methods are known in the art including a diastereomer forming process, a crystal inoculation process, an enzyme process, an isolation film process and a column process. Of such conventional methods, the column process is capable of carrying out optical resolution of optical isomers completely. The column process has another advantage that continuous operation is possible when it is combined with Sarex techniques. However, most of the optical resolution column processes which have been proposed for amino acid separation utilize a ligand exchange process as their resolution principle. Accordingly, it is required to use an eluent containing a metal ion such as a copper ion or the like, or to use an eluent containing another optically active amino acid, if circumstances require. Thus these processes are unsuitable for resolution of an optical isomer.
On the other hand as the column process which does not utilize a ligand exchange principle there has been solely a process using a column filler obtained by chemical bonding (covalent bonding) polystyrene or silica gel with an optically active crown compound (J.Am.Chem.Soc.,97, 1259(1975) and ibid.,101, 3035(1979)). However, this process has disadvantages that not only the number of theoretical plates is small but the preparation of the filler is troublesome and requires high cost. Also, it has another disadvantage in that an organic solvent must be used as an eluent, so that it may not be applied to an aqueous solution of sample to be separated.